Port G - Motorola DragonBall MC68328 User Manual

Parallel Ports
pins are configured as outputs. The actual value on the pin is reported when these bits
are read.
PULLUP - PU[7:0]
These bits enable the pullup resistors on the port. While high, the pullup resistors are
enabled; while low, they are disabled. The pullup resistors are enabled after reset.
SELECT- SEL[7:0]
These bits select whether address or port signals are connected to the pins. While high,
the port I/O function is connected to the pin. While low, the address pins are connect-
ed.The I/O function is selected following reset.

7.1.8 Port G

Port G is multiplexed with timer and serial communication signals. The signals are identified
below. Refer to the timer, PWM, RTC, and UART sections for descriptions of signal func-
tions. All 8 bits are implemented in the registers and each is connected to the outside. As
with other ports, each bit can be individually configured, as needed. The programmer's
model for port G is shown below.
15 14 13 12
DIRECTION
DIR7 DIR6 DIR5 DIR4
Address: $FFFFF430
15 14 13 12
PU7 PU6 PU5 PU4
Address: $FFFFF432
7-10 MC68328 DRAGONBALL PROCESSOR USER'S MANUAL
Table 7-3. Port G Bit Functions
Bit Port Function Other Function
0
1
2
3
4
5
6
7
11 10 9
DIR3 DIR2 DIR1
Figure 7-18. Port G Data/Direction Register
11 10 9
PULLUP
PU3 PU2 PU1
Figure 7-19. Port G Select Register
Bit 0 UART TXD
Bit 1 UART RXD
Bit 2 PWMOUT
Bit 3 TOUT2
Bit 4 TIN2
Bit 5 TOUT1
Bit 6 TIN1
Bit 7 RTCOUT
8 7 6 5
DIR0 D7 D6 D5
8 7 6 5
PU0 SEL7 SEL6 SEL5
4 3 2 1
DATA
D4 D3 D2 D1
Reset Value: $0000
4 3 2 1
SELECT
SEL4 SEL3 SEL2 SEL1
Reset Value: $0000
MOTOROLA
0
D0
0
SEL0